Conference Agenda

We present two distinct types of 'smart' surfaces designed for facilitating the quantitative exploration of dynamic processes occurring at sub-wavelength distances from interfaces, using far-field optical techniques. Based on evanescent waves in excitation and/or emission, we achieve an axial localization precision of about 10 nm. The first type of substrate incorporates nanocavities in a thin metallic film, enhancing and confining the electromagnetic field to a tiny volume. The second sample consists of a thin fluorescent film sandwiched between transparent spacer and capping layers deposited on a glass coverslip. The emission pattern from this film codes detailed information about the local fluorophore environment, namely, the refractive index, defects, reciprocal lattice, and the axial distance of the molecular emitter from the surface. An application to axial metrology in total internal reflection fluorescence and axial super-localisation microscopes is presented.

Emission patterns from molecules at interfaces encode many details about their local environment and their axial position, along the microscope’s optical axis. We introduce an advanced approach that synergizes back focal plane (BFP) imaging with innovative 'smart' surfaces make surface imaging more qualitative, more reliable, and more robust. Our method is particularly focused on accurately measuring the refractive index (RI) of transparent thin films and their imperfections close to the interfaces. Our technique utilizes a 'smart' surface, which features a uniform fluorescent thin film of about 4 nm thickness together with back-focal plane (BFP) imaging. We manage to detect bubbles or other imperfection in 100 nm thin film of polymer with RI of 1.34.

Coherent fiber bundles (CFB) are used in endoscopes for instance in biomedical diagnosis or optical inspection for industrial processes. Their working principle is based on the pixelated intensity transfer via several thousands of fiber cores, within a single monolithic structure. Due to scattering of the effective refractive index in the fiber cores, all phase information is lost. Thus, CFB endoscopes conventionally offer pixelated 2D imaging only, whereas the distal optics used for (de-) magnification enhances the endoscope diameter typically beyond 2 mm and suffers aberrations.

Measuring the optical transfer function of the CFB or more specifically the phase distortion enables correcting said distortion. Advances in CFB endoscopy are presented and discussed. This encompasses single-sided self-calibration and video rate 3D imaging without distal optics based on digital optical phase conjugation using a spatial light modulator. Deep learning is used for real-time complex light field generation as well as image deconvolution. Furthermore, a CFB with bending invariant OTF is introduced. In combination with laser-based manufacturing, this enables an ultrathin and mechanically flexible optical lens. The novel component can be integrated into standard widefield or raster scanning microscopes to enable endoscopic applications with diameters below 400 µm and 1 µm resolution.

The new polarization-holographic element of an optimal configuration is developed for the real-time complete analysis of the polarization state of light (for determining all Stokes parameters). The simultaneous measurement of the intensities in all points of images in diffracted orders using CCD camera and appropriate software allows to determine the spatial distribution of a polarization state in the images of objects, and also the dispersion of this distribution.